Method and system for exploiting spare link bandwidth in a multilane communication channel

ABSTRACT

A system for encoding data in a multilane communication channel may include at least one processor operable to generate, from existing control characters in a character set, expanded control characters utilized for controlling the data in each lane of the multilane communication channel. Each lane of the multilane communication channel may transport the data in a similar direction. The at least one processor is also operable to control at least one of the lanes of the multilane communication channel using at least one of the generated control characters. If a first control character of the existing control characters is a start-of-packet control character, the at least one processor is then operable to select a second control character from any other of the generated expanded control characters, and to indicate a start of a packet using the selected second control character for at least one of the lanes.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application makes reference to, claims priority to, and claims thebenefit of: U.S. Provisional Application Ser. No. 60/448,703 filed Feb.18, 2003; U.S. Provisional Application Ser. No. 60/463,000 filed Apr.15, 2003; and U.S. Provisional Application Ser. No. 60/446,894 filedFeb. 12, 2003.

The above stated applications are incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to encoding of information.More specifically, certain embodiments of the invention relate to amethod and system for encoding information to exploit spare linkbandwidth in a multilane communication channel.

BACKGROUND OF THE INVENTION

Data communication between two link partners or entities in a digitalcommunication system may be accomplished according to the generalconfiguration of FIG. 1. FIG. 1 is a diagram illustrating an embodimentof an existing multilane digital communication link. Referring to FIG.1, there is shown a digital communication link 100, which may includetransmitter side 101 and a receiver side 102. The transmitter side 101may include a multi-lane encoder 103, a high-speed serializer 104 and amodulator 105. The receiver side 102 may include a demodulator 106, ahigh-speed de-serializer 107, and a multi-lane decoder 108. Thetransmitter side 101 and the receiver side 102 may be coupled by a linkinfrastructure 110. Alternatively, the link infrastructure 110 may be aloopback path. Notwithstanding, the link infrastructure may be, forexample, a shielded twisted pair, an unshielded twisted pair (UTP),copper wire or optical fiber.

Typically, the multi-lane encoder 103 may accept raw data bytes from anupstream component of the digital communication system and encode theraw data bytes into a plurality of n parallel lanes 111 a of codedwords. The coded words may be specially designed to provide reliabletransmission over the digital communication link 100. For example,standardized coding such as 4B5B or 8B10B coding may be utilized toensure reliable transmission.

Once the raw bytes of data have been encoded, the resulting coded datamay be multiplexed into a serial bit stream 109 a by the high-speedserializer 104. The serial bit stream 109 a may be transferred to themodulator 105 for processing. The modulator 105 may performdigital-to-analog conversion on the serial bit stream 109 a, resultingin an analog equivalent bitstream 109 b. The resulting analog serialbitstream 109 b may be transferred to the receiver side 102 via the linkinfrastructure or loopback 110.

Once the analog serial bitstream 109 b reaches the demodulator 106 onthe receiver side 102, the demodulator 106 may perform ananalog-to-digital conversion on the serial bit stream 109 b, resultingin a serial digital bitstream 109 c. The resulting serial digitalbitstream 109 c generated by the demodulator 106 may be transferred tothe high-speed de-serializer 107. The de-serializer 107 may perform theopposite function of the serializer 104 and may translate the serialdigital bitstream 109 c back into a plurality of n parallel lanes 111 b.The n parallel lanes 111 b of data are then passed to the multi-lanedecoder 108, which essentially performs the opposite function of theencoder 103 and translates the parallel lanes back into raw data bytes.

An example of a multi-lane protocol interface is a 10 Gigabit AttachmentUnit Interface (XAUI). XAUI is a full duplex interface that may utilizefour data lanes to achieve throughput of 10 gigabits per second. Eachdata lane may operate in parallel at speed of 3.125 gigabits per secondto accommodate data and associated overhead which is generated by the8B/10B coding that is utilized. The resulting data rate is therefore 10gigabits per second.

FIG. 2 is a diagram that illustrates an example of a XAUI parallel lanestructure 200 for 10 gigabit (10 G) BASE-X operation comprising fourlanes. Referring to FIG. 2, the XAUI parallel lane structure 200 mayinclude a first lane (lane 0), a second lane (lane 1), a third lane(lane 2) and a fourth lane (lane 3). The XAUI parallel lane structure200 depicts the end of a first data packet 201, an inter-packet-gap(IPG) or idle 202 and a first portion of a second data packet 203.

The data word bytes in the data packets may be designated by /D/. Theend-of-packet (EOP) word may be designated by the control character /T/and may indicate the end of a data packet. The SOP (start-of-packet)word may be designated by the control character /S/ and may indicate thestart of a data packet. The control character /K/ may indicate a commaand may be utilized for byte alignment. The control character /A/ may beutilized to indicate an alignment character that may used for lanealignment. The control character /R/ may indicate a carrier extend andmay be utilized to separate packets within a burst of packets. Incertain instances, the control character /R/ may be utilized forcode-group alignment. In this regard, the control character /R/ may beused to ensure proper code-group alignment of a first idle characteroccurring after a packet has been transmitted. The IPG or idle packet202 preferably includes control characters such as /A/, /K/, and /R/.Consequently, the IPG or idle packet 202 does not include datacharacters.

The various control characters in each of the parallel lanes, lane 0,lane 1, lane 2 and lane 3 may be part of the transmission protocolutilized by standardized 10 G BASE-X transmission. In accordance withcurrent 10 G standards and protocols, there are 12 control characters orspecial code groups.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with the present invention as set forth inthe remainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

Aspects of the invention include a method for encoding data in amultilane communication channel. The method may include generating fromexisting control characters in a character set, expanded controlcharacters utilized for controlling the data in each lane of themultilane communication channel. At least one of the lanes of themultilane communication channel may be controlled using at least one ofthe generated control characters. The method may further includeselecting a second control character from any other existing controlcharacters if a first control character of the existing controlcharacters is an alignment character. The first control character may becombined with the second control character to generate a third controlcharacter. Each of the combination of the combined first controlcharacter and the second control character may represent an expandedcontrol character. A first logic level may be assigned to the firstcontrol character and a second logic level assigned to the secondcontrol character. The first logic level or the second logic level maybe one of logic zero (0) and logic (1).

If a first control character of the existing control characters is astart-of-packet control character, a second control character may beselected from any other existing control character in a controlcharacter set. A start of a packet may be indicated using the selectedsecond control character. The second control character may be placed ina first lane of the multilane communication channel.

Another aspect of the invention may include determining which lane ofthe multilane communication channel contains an end-of-packet controlcharacter. If the end-of-packet control character is preceded by atleast one control character in a lane of the multilane communicationchannel, then at least one other control character may be selected fromthe existing control character set. The other selected control charactermay be an end-of-packet control character. If the end-of-packet controlcharacter is succeeded by at least one comma control character in a laneof the multilane communication channel, then at least one other controlcharacter may be selected from the existing control character set. Theselected character may be encoded as a comma control character. Themethod may further include generating combinations of the other encodedcontrol character and assigning a unique value to each of the generatedcombinations. Each of the unique values may represent an expandedcontrol character.

In another embodiment of the invention, at least one lane having aninter-packet-gap control character may be located. Any combination ofcontrol characters may be selected from an existing control characterset. A column of the multilane communication channel corresponding to atleast one lane with the inter-packet-gap may be encoded with anycombination of the control characters. At least one column bearing data,for example, a data word, which is bounded by the control characters maybe selected from the existing control character set. At least a firstlane and a last lane of at least one column of the multilanecommunication channel may be encoded with the control charactersselected from the existing control character set. The expanded controlcharacter may utilize spare link bandwidth. The existing controlcharacters may be one of a configuration character, an idle characterand an encapsulation character.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section for encoding data in a multilane communication channel. Theat least one code section may be executable by a machine, therebycausing the machine to perform the steps for encoding data in amultilane communication channel as described above.

A further aspect of the invention provides a system for encoding data ina multilane communication channel. The system may include at least onegenerator which may generate from existing control characters in acharacter set, expanded control characters utilized for controlling thedata in each lane of the multilane communication channel. At least onecontroller may control at least one of the lanes of the multilanecommunication channel using at least one of the generated controlcharacters. A selector may select a second control character from anyother of the existing control characters if a first control character ofthe existing control characters is an alignment character. A combinermay combine the first control character with the second controlcharacter to generate a third control character. Each of the combinationof the combined first control character and the second control charactermay represent the expanded control character. An assignor may assign afirst logic level to the first control character and to assign a secondlogic level to the second control character. The first logic level andthe second logic level is one of logic zero (0) and logic (1).

In another aspect of the invention, the selector may select a secondcontrol character from any other of the existing control characters if afirst control character of the existing control characters is astart-of-packet control character. The selected second control charactermay indicate the start of a packet. The controller may place the secondcontrol character in a first lane of the multilane communicationchannel. The controller may also determine which lane of the multilanecommunication channel contains an end-of-packet control character.

The selector may select at least one other control character from theexisting control character set if the end-of-packet control character ispreceded by at least one control character in a lane of the multilanecommunication channel. An encoder may encode the selected at least oneother control character as the end-of-packet control character. Theselector may also select at least one other control character from theexisting control character set if the end-of-packet control character issucceeded by at least one comma control character in a lane of themultilane communication channel. The encoder may encode the selectedcontrol character as the comma control character. The generator maygenerate combinations of the encoded control character. The assignor mayassign a unique value to each of the generated combinations of theencoded control character. Each of the assigned unique values mayrepresent an expanded control character.

In another aspect of the invention, the controller may determine atleast one lane of the multilane communication channel that has aninter-packet-gap control character. The selector may select anycombination of control characters from the existing control characterset. The encoder may encode a column of the multilane communicationchannel corresponding to the determined lane with the selected anycombination of control characters. The generator may generate at leastone column bearing, for example, a data word, bounded by controlcharacters selected from the existing control character set. The encodermay encode at least a first lane and a last lane of at least one columnof the multilane communication channel with the control charactersselected from the existing control character set.

In accordance with the various embodiments of the invention, theexpanded control character may utilize spare link bandwidth. Theexisting control characters may be a configuration character, an idlecharacter or an encapsulation character, for example.

These and other advantages, aspects and novel features of the presentinvention, as well as details of a illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a current multilanedigital communication link.

FIG. 2 is a diagram that illustrates an example of a XAUI parallel lanestructure 200 for 10 gigabit (10 G) BASE-X operation comprising fourlanes.

FIG. 3 is a diagram illustrating an embodiment of an enhanced encodingmethod specifically showing the encoding of lane alignment controlcharacters /A/, in accordance with an embodiment of the invention.

FIG. 4 is a diagram illustrating an embodiment of the enhanced encodingmethod of FIG. 3 specifically showing the encoding of a start-of-packetcontrol character /S/ in accordance an embodiment of the presentinvention.

FIG. 5 is a diagram illustrating an embodiment of the enhanced encodingmethod of FIG. 3 specifically showing the encoding of an end-of-packetcontrol character /T/, in accordance with an embodiment of the presentinvention.

FIG. 6 is a diagram illustrating an embodiment of the enhanced encodingmethod of FIG. 3 specifically showing the encoding of control charactersin an inter-packet-gap, in accordance with and embodiment of theinvention.

FIG. 7 is a diagram illustrating an embodiment of the enhanced encodingmethod of FIG. 3 specifically showing the encoding of data words boundedby control characters, in accordance with an embodiment of theinvention.

FIG. 8 is a block diagram of an exemplary system 800 for encoding datain a multilane communication channel in accordance with an embodiment ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the present invention relate to exploiting sparelink bandwidth in a multi-lane communication channel, using an enhancedencoding method, to effectively expand the utilized information capacityof the multi-lane communication channel. Accordingly, aspects of theinvention may include a method for encoding data in a multilanecommunication channel. The method may include generating from existingcontrol characters in a character set, an expanded control characterwhich may be utilized for controlling data in each lane of the multilanecommunication channel. The expanded control character may utilize sparelink bandwidth. At least one of the lanes may be controlled using atleast one of the generated existing control characters. If a firstcontrol character is an alignment character, a second control charactermay be selected from any other existing control characters. The firstcontrol character may be combined with the second control character togenerate a third control character. Each of the combinations of thefirst and second control characters may represent an expanded controlcharacter. The existing control characters may be a configurationcharacter, an idle character or an encapsulation character.

FIG. 3 is a diagram 300 illustrating an embodiment of an enhancedencoding method specifically showing the encoding of lane alignmentcontrol characters /A/, in accordance with an embodiment of theinvention. The lane alignment control character /A/ is a character thatmay appear in each of the lanes of a multi-lane transmission. The lanealignment control character /A/ may be utilized to align the parallellanes with each other. In the case of a XAUI, the lane alignment controlcharacter may be utilized to align each of lane 0, lane 1, lane 2 andlane 3 with each other. Referring to FIG. 2, reference 204 illustratesan exemplary lane alignment characters in each of the XAUI lanes, lane0, lane 1, lane 2 and lane 3.

In an embodiment of the invention, the lane alignment control charactermay not be limited to the /A/ control character. Accordingly, theprotocol may include a lane alignment character that may have at leasttwo control characters. In this regard, the lane alignment character /A/may be combined with a second control character and the combined controlcharacters may be utilized for lane alignment. For example, in a casewhere a second lane alignment character such as /A′/ is utilized, thenthe /A/ and /A′/characters may be simultaneously utilized for lanealignment. The /A′/ control character may be any one of the otheravailable control characters in the protocol.

In order to add encoded information, the control character /A/ mayrepresent logic “1” and the control character /A′/ may represent logic“0”. As a result, the two control characters /A/ and /A′/ may beutilized for lane alignment and as four additional bits of informationthat may be transmitted. Accordingly, the /A/ and the /A′/ controlcharacters may utilize spare link bandwidth. The following tableillustrates possible combinations for the control characters /A/, /A′/for a XAUI.

LANE 0 LANE 1 LANE 2 LANE 3 0 /A/ /A/ /A/ /A/ 1 /A/ /A/ /A/ /A′/ 2 /A//A/ /A′/ /A/ 3 /A/ /A/ /A′/ /A′/ 4 /A/ /A′/ /A/ /A/ 5 /A/ /A′/ /A/ /A′/6 /A/ /A′/ /A′/ /A/ 7 /A/ /A′/ /A′/ /A′/ 8 /A′/ /A/ /A/ /A/ 9 /A′/ /A//A/ /A′/ 10 /A′/ /A/ /A′/ /A/ 11 /A′/ /A/ /A′/ /A′/ 12 /A′/ /A′/ /A/ /A/13 /A′/ /A′/ /A/ /A′/ 14 /A′/ /A′/ /A′/ /A/ 15 /A′/ /A′/ /A′/ /A′/

For example, if the lane alignment characters transmitted in each laneare, lane 0: /A′/, lane 1: /A/, lane 2: /A/ and lane 3: /A′/, this mayrepresent the four (4) bits of information 0, 1, 1, 0. With four (4)bits, there are 2⁴ or 16 possible combinations that may be encoded, eachof which may be utilized to represent a different unit of information.In one aspect of the invention, the four (4) bits of lane alignmentcontrol characters may be encoded in order to transmit statusinformation or other system information, for example. The followingtable illustrates exemplary logic assignments for various combinationsof control characters /A/, /A′/ for a XAUI as described in the tableabove.

LANE 0 LANE 1 LANE 2 LANE 3 0 1 1 1 1 1 1 1 1 0 2 1 1 0 1 3 1 1 0 0 4 10 1 1 5 1 0 1 0 6 1 0 0 1 7 1 0 0 0 8 0 1 1 1 9 0 1 1 0 10 0 1 0 1 11 01 0 0 12 0 0 1 1 13 0 0 1 0 14 0 0 0 1 15 0 0 0 0

The first exemplary combination or encoding, namely 0, which has lane 0:/A/, lane 1: /A/, lane 2: /A/ and lane 3: /A/ may represent the standardassignment for lane alignment. However, the remaining encodedcombinations, namely 1 through 15, may represent expanded or additionalassignments that may be utilized for communicating status or othersystem information.

In another embodiment of the invention, a start-of-packet (SOP) controlcharacter, which may be represented as a /S/ control character, may alsobe encoded. FIG. 4 is a diagram 400 illustrating an embodiment of theenhanced encoding method of FIG. 3 specifically showing the encoding ofa start-of-packet control character /S/ in accordance an embodiment ofthe present invention. The start-of-packet control character /S/, maynormally appear in lane 0 of a multilane communication channelstructure. The start-of-packet control character /S/, may be utilized tosignify the start of a next data packet, symbol or codeword by itself.Referring to FIG. 2, reference 206 depicts a start-of-packet controlcharacter /S/.

In one embodiment of the invention, any control character in an existingcontrol character set may be utilized to define an expanded or newstart-of-packet control character that may represent the start of a nextpacket. Referring to FIG. 4, the expanded or new start-of-packetcharacter may be represented by /Y/, for example. The expanded or newstart-of-packet control character is referenced by 402. The expanded ornew start-of-packet control character 402 may represent the start of anew packet and may be located or placed in the first lane, lane 0. Theexpanded start-of-packet control character 402 may be succeeded by orfollowed by data words, /D/, in each of the successive lanes, lane 1,lane 2 and lane 3. As a result, each unique control character /Y/ in astart-of-packet lane sequence may represent a different unit ofinformation. For example, if there are 12 control characters in thecontrol character set, then 11 additional units of information may becommunicated as part of a start-of-packet control character.Notwithstanding, the additional units of information or expandedstart-of-packet control characters may utilize spare link bandwidth.

In another embodiment of the invention, an end-of-packet (EOP) controlcharacter, which may be represented as a IT/ control character, may alsobe encoded. FIG. 5 is a diagram 500 illustrating an embodiment of theenhanced encoding method of FIG. 3 specifically showing the encoding ofan end-of-packet control character /T/, in accordance with an embodimentof the present invention. The end-of-packet control character /T/, mayappear in any lane of a multi-lane structure and may be preceded by datawords /D/ and/or followed by comma control characters /K/. Theend-of-packet control character /T/ may also be utilized to define theend of a current data packet, symbol or control word all by itself.Although /T/ and /K/ control characters are illustrated in FIG. 5, theinvention is not so limited and any other control characters in theexisting control character set may be utilized.

In accordance with an aspect of the invention, whenever an end-of-packetcontrol character is preceded by data words /D/, subsequentend-of-packet control characters /T/ and/or comma control characters /K/may be encoded as any available control character such as /Y/. Forexample, referring to FIG. 5, in a case where there are four (4) lanesand the end-of-packet sequence would be lane 0: /D/, lane 1: /D/, lane2: /D/, and lane 3: /T/, as referenced by 502, then the /T/ in lane 3may be encoded as any available control character /Y/. This may resultin expanded or additional control characters that may provide additionalunits of information, which communicates status or other systeminformation. The additional units of information or expandedend-of-packet control characters may utilize spare link bandwidth.

Similarly, in instances where the end-of-packet sequence would be lane0: /D/, lane 1: /D/, lane 2: /T/ and lane 3: /K, as referenced by 504,then the /T/ control character in lane 2 and the control character /K/in lane 3 may be encoded with any combination of available controlcharacters. This may result in expanded or additional control charactersand may provide additional units of information that communicates statusor other system information. The additional units of information orexpanded end-of-packet control characters may utilize spare linkbandwidth.

Additionally, in instances where the end-of-packet sequence would belane 0: D, lane 1: /T/, lane 2: /K/ and lane 3: /K/, as referenced by506, then the /T/ control character in lane 1, the /K/ control characterin lane 2, and the /K/ control character in lane 3 may be encoded withany combination of available control characters. In this regard, thesequence of two (2) /K/ control characters in lane 2 and lane 3 may beencoded as two (2) bits of additional information. For example, the two(2) /K/ control characters may be encoded as /K/ or /K′/ where /K′/ is adifferent control character from /K/ and may be one of the controlcharacters in the existing control character set. In this manner, the/K/ control character may represent logic one (1) and the /K′/ mayrepresent logic zero (0), thereby providing 2 bits of additionalinformation in the EOP sequence. This may result in expanded oradditional control characters and may provide additional units ofinformation that communicates status or other system information. Theadditional units of information or expanded end-of-packet controlcharacters may utilize spare link bandwidth.

Finally, in instances where the end-of-packet sequence would be lane 0:/T/, lane 1: /K/, lane 2: /K/ and lane 3: /K/, as referenced by 508,then the sequence of three (3) /K/ control characters in lane 1, lane 2and lane 3 may be encoded as three (3) bits of additional information.Again, this may result in expanded or additional control characters andmay provide additional units of information that communicates status orother system information. The additional units of information orexpanded end-of-packet control characters may utilize spare linkbandwidth. For example, the three (3) /K/ control characters may beencoded as /K/ or /K′/ where /K′/ is a different control character from/K/ and may be one of the control characters in the existing controlcharacter set. In this manner, the /K/ control character may representlogic one (1) and the /K′/ may represent logic zero (0), therebyproviding 3 bits of additional information in the EOP sequence. Otherencoding schemes for this EOP sequence may be implemented withoutdeparting from the spirit or essence of the various embodiments of thepresent invention.

Another embodiment of the invention may provide encoding of controlcharacters in an idle or inter packet gap (IPG). FIG. 6 is a diagram 600illustrating an embodiment of the enhanced encoding method of FIG. 3specifically showing the encoding of control characters in aninter-packet-gap, in accordance with an embodiment of the invention. Aninter-packet-gap or idle control character may occur between two datapackets in a multilane communication channel. The inter-packet-gap mayinclude comma control characters /K/ and carrier extend controlcharacters /R/. In general, the inter-packet-gap control characters maybe the same in any given column of a parallel multilane channelstructure. Referring to FIG. 2, reference 208 depicts an idle orinter-packet-gap control character.

Within an inter-packet-gap, a column of control characters across theparallel lanes of a multilane communication channel may be encoded usingany combination of available control characters such as /Y/ inaccordance with an embodiment of the invention. This may result inexpanded or additional inter-packet-gap control characters and mayprovide additional units of information that communicates status orother system information. The additional units of information orexpanded inter-packet-gap control characters may utilize spare linkbandwidth. In a further aspect of the invention, multiple columns ofcontrol characters within an inter-packet-gap may also be encoded in asimilar manner to add even more information to the inter-packet-gap.

Referring to FIG. 6, a column containing /K/ control characters 602,which may represent an inter-packet-gap or idle control character, maybe encoded using any combination of control characters in the controlcharacter set. In this regard, /Y/ may represent a selected controlcharacter from the control character set. Possible combinations of theselected control character /Y/ may be represented by /Y_(i)/, /Y_(j)/,/Y_(k)/and /Y_(i)/. Similarly, a column containing /R/ controlcharacters 604, which may represent an inter-packet-gap or idle controlcharacter, may be encoded using any combination of control characters inthe control character set. Accordingly, the /R/ control characters maybe encoded using any possible combinations and may be represented by/Y_(i)/, /Y_(j)/, /Y_(k)/ and /Y_(i)/.

Another embodiment of the invention may include the creation orgeneration of new columns of control characters, data words, codewordsand/or symbols, which may be placed in a multilane communicationchannel. FIG. 7 is a diagram 700 illustrating an embodiment of theenhanced encoding method of FIG. 3 specifically showing the encoding ofdata words bounded by control characters, in accordance with anembodiment of the invention. In FIG. 7, newly created columns of controlcharacters /Y/and data words /D/ may be inserted into a multilanedatastream for a communication channel.

Referring to FIG. 7, three (3) exemplary configuration columns 702, 704and 706, of data words /D/ bounded by control characters /Y/ areillustrated. Expanded information may be encoded in the data words /D/and may be bounded by control characters /Y/. The control characters /Y/may be any combination of control characters in the control characterset. Certain configurations of control characters /Y/ and data words /D/may define specific types of communicated information. Accordingly, thismay result in additional control characters and may provide additionalunits of information that may communicates status or other systeminformation. The additional units of information or expanded controlcharacters may utilize spare link bandwidth.

For example, configuration column 702 illustrates lane 0: /Y/, lane 1:/D/, lane 2: /Y/ and lane 3: Y and configuration column 704 illustrateslane 0: /Y/, lane 1: /D/, lane 2: /D/ and lane 3: /Y/. The configurationcolumn 706 having lane 0: /Y/, lane 1: /D/, lane 2: /D/ and lane 3: /Y/may be generated to represent two bytes of status information such aserror information. If each data word /D/ is 8 bits, for example, theneach /D/ may be encoded to provide up to 28 or 256 different units ofinformation. The newly encoded configuration columns 702, 704 and 706illustrate ID/ data words bounded by control characters /Y/. The newcolumns of added information may be inserted in the parallel lanestructure of a multilane channel. In this regard, the new columns andadded information may be inserted within data packets and/or withininter-packet-gaps, for example. The insertion of new columns of addedinformation may result in the additional bytes being added to theparallel datastream in the multilane channel. However, the additionalbytes are added to the parallel data stream such that the additionalinformation that is carried by the additional bytes out weighs theoverhead associated with the additional bytes.

Other embodiments that may take advantage of spare link bandwidth, mayalso be implemented. For example, the /K/ control character may compriseseven (7) fixed bits and three (3) don't care bits (xxx) according to8B/10B encoding protocol, thereby resulting in a codeword of 0011111xxx.The protocol may be modified such that the three (3) don't care bitsxxx, may be encoded with 2³ or 8 different units of additionalinformation in accordance with an embodiment of the present invention.Notwithstanding, although a XAUI is utilized to illustrate variousembodiment or aspects of the invention, the enhanced encoding methodsare applicable to other encoding schemes that may utilize multiplelanes, in accordance with various embodiments of the present invention.

FIG. 8 is a block diagram of an exemplary system 800 for encoding datain a multilane communication channel in accordance with an embodiment ofthe invention. The system 800 may include an assignor 802, a selector804, an encoder 806, a controller 808, a combiner 810 and a generator812. Referring to FIG. 8, the generator 812 may generate from existingcontrol characters in a character set, expanded control charactersutilized for controlling the data in each lane of the multilanecommunication channel. The controller 808 may control at least one ofthe lanes of the multilane communication channel using at least one ofthe generated control characters. The selector 804 may select a secondcontrol character from any other of the existing control characters if afirst control character of the existing control characters is analignment character. The combiner 810 may combine the first controlcharacter with the second control character to generate a third controlcharacter. Each of the combination of the combined first controlcharacter and the second control character may represent the expandedcontrol character. The assignor 802 may assign a first logic level tothe first control character and to assign a second logic level to thesecond control character. The first logic level and the second logiclevel is one of logic zero (0) and logic (1).

In another aspect of the invention, the selector 804 may select a secondcontrol character from any other of the existing control characters if afirst control character of the existing control characters is astart-of-packet control character. The selected second control charactermay indicate the start of a packet. The controller 808 may place thesecond control character in a first lane of the multilane communicationchannel. The controller 808 may also determine which lane of themultilane communication channel contains an end-of-packet controlcharacter.

The selector 804 may select at least one other control character fromthe existing control character set if the end-of-packet controlcharacter is preceded by at least one control character in a lane of themultilane communication channel. The encoder 806 may encode the selectedat least one other control character as the end-of-packet controlcharacter. The selector 804 may select at least one other controlcharacter from the existing control character set if the end-of-packetcontrol character is succeeded by at least one comma control characterin a lane of the multilane communication channel. The encoder 806 mayencode the selected control character as the comma control character.The generator 812 may generate combinations of the encoded controlcharacter. The assignor 802 may assign a unique value to each of thegenerated combinations of the encoded control character. Each of theassigned unique value may represent an expanded control character.

In another aspect of the invention, the controller 808 may determine atleast one lane of the multilane communication channel that has aninter-packet-gap control character. The selector 804 may select anycombination of control characters from the existing control characterset. The encoder 806 may encode a column of the multilane communicationchannel corresponding to the determined lane with the selected anycombination of control characters. The generator 812 may generate atleast one column bearing, for example a data word, bounded by controlcharacters selected from the existing control character set. The encoder806 may encode at least a first lane and a last lane of at least onecolumn of the multilane communication channel with the controlcharacters selected from the existing control character set. Inaccordance with the various embodiments of the invention, the expandedcontrol character may utilizing spare link bandwidth. The existingcontrol characters may be a configuration character, an idle characteror an encapsulation character, for example.

In another embodiment of the invention, the /S/ control character may befurther employed to utilize unused bandwidth. In this regard, the /S/control character may not be limited to lane 0, but may be utilized inother lanes as well. For example, in a four (4) lane XAUI arrangement,the /S/ control character may occur in lanes 1, 2 and/or 3. Accordingly,in the four (4) lane XAUI system, there would be two (2) additional bitsof information that may be passed depending on the lane in which lanethe /S/ control character is located. For example, lane 0 may berepresented by binary 00, lane 1 by binary 01, lane 2 by binary 10 andlane 3 by binary 11.

In summary, a method is provided that exploits spare link bandwidth in amulti-lane communication channel using an enhanced encoding scheme, toeffectively expand the utilized information capacity of a multilanecommunication channel. Existing control character protocol may beenhanced to permit the embedding of additional information in themultilane communication channel. The additional information may includevarious system and status information.

While the invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the invention without departing from its scope.Therefore, it is intended that the invention not be limited to theparticular embodiment disclosed, but that the invention will include allembodiments falling within the scope of the appended claims.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in one computersystem, or in a distributed fashion where different elements are spreadacross several interconnected computer systems. Any kind of computersystem or other apparatus for carrying out the methods described hereinis suited. A typical combination of hardware and software may be ageneral-purpose computer system with a computer program that, when beingloaded and executed, controls the computer system such that it carriesout the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1-60. (canceled)
 61. A system for encoding data in a multilanecommunication channel, the system comprising: at least one processoroperable to generate, from existing control characters in a characterset, expanded control characters utilized for controlling the data ineach lane of the multilane communication channel, wherein each lane ofthe multilane communication channel transports the data in a similardirection; said at least one processor operable to control at least oneof said lanes of the multilane communication channel using at least oneof said generated control characters; and said at least one processoroperable to: select a second control character from any other of saidgenerated expanded control characters; and indicate a start of a packetusing said selected second control character for at least one of saidlanes, if a first control character of said existing control charactersis a start-of-packet control character.
 62. The system according toclaim 61, wherein said at least one processor is operable to place saidsecond control character in a first lane of the multilane communicationchannel.
 63. A system for encoding data in a multilane communicationchannel, the system comprising: one or more circuits operable togenerate, from existing control characters in a character set, expandedcontrol characters utilized for controlling the data in each lane of themultilane communication channel, wherein each lane of the multilanecommunication channel transports the data in a similar direction; saidone or more circuits operable to control at least one of said lanes ofthe multilane communication channel using at least one of said generatedcontrol characters; and said one or more circuits operable to: select asecond control character from any other of said generated expandedcontrol characters; and indicate a start of a packet using said selectedsecond control character for at least one of said lanes, if a firstcontrol character of said existing control characters is astart-of-packet control character.
 64. The system according to claim 63,wherein said one or more circuits is operable to place said secondcontrol character in a first lane of the multilane communicationchannel.
 65. A system for encoding data in a multilane communicationchannel, the system comprising: at least one processor operable togenerate, from existing control characters in a character set, expandedcontrol characters utilized for controlling the data in each lane of themultilane communication channel, wherein each lane of the multilanecommunication channel transports the data in a similar direction; saidat least one processor operable to control at least one of said lanes ofthe multilane communication channel using at least one of said generatedcontrol characters; and said at least one processor operable todetermine which lane of the multilane communication channel contains anend-of-packet control character.
 66. The system according to claim 65,wherein said at least one processor is operable to: select at least oneother control character from said existing control character set, ifsaid end-of-packet control character is preceded by at least one controlcharacter in a lane of the multilane communication channel; and encodesaid selected at least one other control character as said end-of-packetcontrol character.
 67. The system according to claim 65, wherein said atleast one processor is operable to: select at least one other controlcharacter from said existing control character set, if saidend-of-packet control character is succeeded by at least one commacontrol character in a lane of the multilane communication channel; andencode said selected at least one other control character as said commacontrol character.
 68. The system according to claim 67, herein said atleast one processor is operable to generate combinations of said encodedat least one other control character.
 69. The system according to claim68, herein said at least one processor is operable to assign a uniquevalue to each of said generated combinations of said encoded at leastone other control character.
 70. The system according to claim 69,wherein each of said assigned unique values represents an expandedcontrol character.
 71. A system for encoding data in a multilanecommunication channel, the system comprising: one or more circuitsoperable to generate, from existing control characters in a characterset, expanded control characters utilized for controlling the data ineach lane of the multilane communication channel, wherein each lane ofthe multilane communication channel transports the data in a similardirection; said one or more circuits operable to control at least one ofsaid lanes of the multilane communication channel using at least one ofsaid generated control characters; and said one or more circuitsoperable to determine which lane of the multilane communication channelcontains an end-of-packet control character.
 72. The system according toclaim 71, wherein said one or more circuits is operable to: select atleast one other control character from said existing control characterset, if said end-of-packet control character is preceded by at least onecontrol character in a lane of the multilane communication channel; andencode said selected at least one other control character as saidend-of-packet control character.
 73. The system according to claim 71,wherein said one or more circuits is operable to: select at least oneother control character from said existing control character set, ifsaid end-of-packet control character is succeeded by at least one commacontrol character in a lane of the multilane communication channel; andencode said selected at least one other control character as said commacontrol character.
 74. The system according to claim 73, herein said oneor more circuits is operable to generate combinations of said encoded atleast one other control character.
 75. The system according to claim 74,herein said one or more circuits is operable to assign a unique value toeach of said generated combinations of said encoded at least one othercontrol character.
 76. The system according to claim 75, wherein each ofsaid assigned unique values represents an expanded control character.77. A system for encoding data in a multilane communication channel, thesystem comprising: at least one processor operable to generate, fromexisting control characters in a character set, expanded controlcharacters utilized for controlling the data in each lane of themultilane communication channel, wherein each lane of the multilanecommunication channel transports the data in a similar direction; saidat least one processor operable to control at least one of said lanes ofthe multilane communication channel using at least one of said generatedexpanded control characters; and said at least one processor operable toutilize, during said controlling, spare link bandwidth by said generatedexpanded control character.
 78. A system for encoding data in amultilane communication channel, the system comprising: one or morecircuits operable to generate, from existing control characters in acharacter set, expanded control characters utilized for controlling thedata in each lane of the multilane communication channel, wherein eachlane of the multilane communication channel transports the data in asimilar direction; said one or more circuits operable to control atleast one of said lanes of the multilane communication channel using atleast one of said generated expanded control characters; and said one ormore circuits operable to utilize, during said controlling, spare linkbandwidth by said generated expanded control character.